Yes you've been unlucky with customs and I've only had this happen ounce in 6yrs but 3 weeks from China still isn't bad and if that order was for machined ballscrews then I assure you you wouldn't have got them done and delivered much quicker in this country, I know others who have and it's taken much longer than 3 weeks and cost 3 times the price.!!

Anyway you have them now so Crack on.!!